How do I add Root bone to a character's rig?

I rigged my character but couldn’t understand what’s the role of a root bone so I couldn’t add any, tried to follow youtube tutorials, rigging in Mixamo and using blender plugin to add root bone but that didn’t work. What’s the mothod to add a root bone? I also can’t find a video about adding a fake root bone, any help?

The root bone is mainly for root motion purposes. If yours don’t use root motion, then just skipped it. It’s the parent bone for the rig.

Another way to achieve a similar result is just to translate the whole character.